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Topic Review (Newest First)

12-18-2011 07:30 PM

67-4-fun

run two 390's for street use, you will be much happier than two 450's at least for a SBC

12-18-2011 03:00 PM

blight

I know this is a very old topic. - Are there any updates seen since the last post on this topic?

02-10-2007 12:15 PM

xntrik

Fuel distribution is more important than most people realize. SFI is equal air and equal fuel, right?

Check out the new Barry Grant inline 4bbl for smooth fuel distribution. Far superior to any single 4 bbl.

Multi carb, 2x2, 3x2, 4x2, 6x2, etc, all came about because there were NO 4bbl carbs until 56 or so, then limited production, no manifolds available, and very expensive. Then 4x2.

Finally single 4bbl became the standard that most people think is THE BEST. It is only convenient, less expensive, and more trouble free. Early versions had 3" runners mixed with 10" runners, e.g. GT-350 Cobra, F4B, etc.

Tunnel rams equaled runners out at about 6 to 10", and smoothed fuel distribution across the board= more power across the board.

Look at the runners in the new generation single 4bbl intakes, Perf RPM, Air Gap, etc.

02-10-2007 09:38 AM

Crazy Mopar Guy

Quote:

Need to send that article to Detroit. Maybe GM, Ford & Mopar should be putting tunnel rams on all their grocery getters, sure sound like it would be better than the manifolds they are using now.

I think GM, Ford and Mopar are losing enough money as it is!

Tunnel rams aren't "best" in every scenario obviously, but because they are not used OEM does not mean they are an inferior product.
What's better- Jesel belt, or a nylon tooth timing set? An ATI Superdamper or OEM damper?
Etc etc.

Tunnel rams aren't cost efficient, they don't lend themselves to low, sleek hoodlines, and since a single 4bbl platform suffices in almost all factory endeavors, there really is no reason for the manufacturers to even look at tunnel rams for OEM use.

I can't think of the last 3x2bbl or dual 4bbl factory car since the early 1970s in fact?

02-10-2007 09:35 AM

pal

hope its okay to jump in here and ask for advice? i have used multi carb set-ups in the 70s and loved them. today i am putting together a street truck, just to drive now and then for fun factor only. i would like to run tunnel ram with 2 fours. everyone has talked me out of using a cross ram (i think they are the coolest in the looks department. since several of you guys are experienced with the tunnel ram, would you please advise me on what would be some of the decent combos to watch for? i love to buy used or swap meets. my set-up is as follows. 3700 lbs., 4 speed Muncie, 3.73 or 4.10 with 31 inch tall tire. 406Sb, old school camel backs 2.02/1.6 heads with some porting and bowl work. 9.3:1 CR, bullet solid lifter cam that they recommenced-278/286 duration at seat-108 LOB-530/552 gross valve lift-248/256 duration at .050. long tube hookers. i am not a machinist so modifying is not up my alley, but will try anything once. would love to try building a sheet metal intake, but i am not qualified for that. cam i have is 2500-6400 rated. i think it will be a little different then that on 400 inch motor. i will mostly run engine to 5500 with some 6000 blast. any recommendations?

02-10-2007 12:49 AM

willys36@aol.com

Quote:

Originally Posted by xntrik

QUOTE Originally Posted by xntrik
Popular Hot Rodding Magazine, December 2006, THE X FACTOR, p 75, David Vizard.

He back to back tests a SBC 383 with Holley Strip Dominator and the Weiand Tunnel Ram and the tunnel ram won across the board from below 3500 to 7500 rpm.
QUOTE
**********************************************
I did not run that test nor write that article. I am only pointing it out.

Look at the dyno charts..

At 3500 the tunnel ram was 30 above the other and the lines were NOT convergent downward. They were parallel.

They didn't pull it at 2500 so who knows.
************************************************
But he probably is one of those lying magazine writers anyway.. ... they'll lie about anything to promote some rich advertisers' products..

Isn't that what many people believe?????

Need to send that article to Detroit. Maybe GM, Ford & Mopar should be putting tunnel rams on all their grocery getters, sure sound like it would be better than the manifolds they are using now.

02-09-2007 12:05 PM

Crazy Mopar Guy

Quote:

Originally Posted by wyomingoutlaw

I only care about that .001% of the time when I put my foot to the floor

sorry, I couldn't help myself. anyways, I've certainly done my research on tunnel rams, so I'm going to give mine a whirl. I just plunked $250 down on a new junk yard hood (the last one got cut to pieces thanks to that victor...) and before any holes will be cut I am going to run it against a torker II with a 800 vac. it'll be easy to test the two since I wont have to pull the distributor or the water cross over (gotta love those pontiacs...), anyways I digress. I'll let ya'll know how they both performed.

Most common problem I see when guys run tunnel rams are OVERcarbing and having one or both carbs being problematic. I used to run one carb at a time on a 360 4bbl car I had when guys would complain their tunnel rams wouldn't work right, usually it was a carb pissing fuel, stuck with varnish etc.
A single 4bbl or 2 4bbl vehicle can't use carbs that have been on a shelf for ten years without a kit, and likewise the carbs bought at swap meets that sat in the rain for a dozen times aren't good candidates either.
Run each carb if you can, and tell us what happens!

02-09-2007 12:01 PM

Crazy Mopar Guy

I never used the long ram intakes (I assume that's what you refer to from 1960) because we could never find them affordably and they were said to hit a shock tower on B body cars, which is what we wanted to run them on.
They were advertised as strong mid rpm performers, many 4x4 guys have used them.

02-09-2007 02:53 AM

xntrik

Crazy Mopar Guy that intake is awesome looking.

We have 2 1960 cross rams, one on a 440 magnum and one on a 426 wedge being built right now.

The 440 was awesome (its on the engine stand now).

02-09-2007 02:47 AM

xntrik

QUOTE Originally Posted by xntrik
Popular Hot Rodding Magazine, December 2006, THE X FACTOR, p 75, David Vizard.

He back to back tests a SBC 383 with Holley Strip Dominator and the Weiand Tunnel Ram and the tunnel ram won across the board from below 3500 to 7500 rpm.
QUOTE
**********************************************
I did not run that test nor write that article. I am only pointing it out.

Look at the dyno charts..

At 3500 the tunnel ram was 30 above the other and the lines were NOT convergent downward. They were parallel.

They didn't pull it at 2500 so who knows.
************************************************
But he probably is one of those lying magazine writers anyway.. ... they'll lie about anything to promote some rich advertisers' products..

Isn't that what many people believe?????

02-09-2007 01:42 AM

wyomingoutlaw

Quote:

Originally Posted by willys36@aol.com

Tunnels are great for drag racing for which they are intended and for looking mean on the street. However, if used in the latter application they will perform poorly at the rpms encountered 99.999% of the time.

I only care about that .001% of the time when I put my foot to the floor

sorry, I couldn't help myself. anyways, I've certainly done my research on tunnel rams, so I'm going to give mine a whirl. I just plunked $250 down on a new junk yard hood (the last one got cut to pieces thanks to that victor...) and before any holes will be cut I am going to run it against a torker II with a 800 vac. it'll be easy to test the two since I wont have to pull the distributor or the water cross over (gotta love those pontiacs...), anyways I digress. I'll let ya'll know how they both performed.

02-08-2007 11:57 PM

Crazy Mopar Guy

Quote:

Originally Posted by willys36@aol.com

Don't doubt those results. Tunnels are super power makers if you keep the velocity up. Basically a poor boy's set of injector stacks. Unfortunately, "from below 3500rpm to 7500rpm" is WAY outside the range you use for street driving. It is a rare situation you ever get anywhere near 3500rpm unless you are running 4:11 or lower gears but that is the topic of another article altogether!! Magazine articles praising this and that piece of power equipment are of dubious value at best. Those authors are usually slack-jawed mouth breathers just out of high school and get the facts pretty much wrong the majority of the time. Divide that rpm range by 3 and you are in the ball park of what it will see on the street. As Crazy Mopar Guy says they can be made to run pretty well on the street but I guarantee they aren't running as efficiently and with as much power as a dual plane manifold at street rpms. It isn't magic, just basic physics. A friend of mine ran a radical cross-ram w/ dual Holley 600s on his SBC. It ran but a dual plane would have been a lot better. As stated before, they were designed for WOT high speed drag racing and impressing chicks at Sonic on Friday night. Running them on a daily driver is a compromise as is all engine design.

I COMPLETELY disagree with the "Basically a poor boy's set of injector stacks."
Injector stacks are individual runner intakes, and are completely different.

My work truck was driven for years with a mild cam (268 Comp) mild compression (9.7) and a stock converter. It was VERY heavy, and I towed trailers. It had unbelievable low end torque. 2 Holley center float 450cfm carbs on a modified 3x2bbl Weiand tunnel ram, converted to 2x4bbls, with ported runners to boot! It could spin the tires for a loooooong time, tow a trailer, and performed no different than a good running 4bbl intake.

02-08-2007 11:08 PM

willys36@aol.com

Quote:

Originally Posted by xntrik

Popular Hot Rodding Magazine, December 2006, THE X FACTOR, p 75, David Vizard.

He back to back tests a SBC 383 with Holley Strip Dominator and the Weiand Tunnel Ram and the tunnel ram won across the board from below 3500 to 7500 rpm.

Don't doubt those results. Tunnels are super power makers if you keep the velocity up. Basically a poor boy's set of injector stacks. Unfortunately, "from below 3500rpm to 7500rpm" is WAY outside the range you use for street driving. It is a rare situation you ever get anywhere near 3500rpm unless you are running 4:11 or lower gears but that is the topic of another article altogether!! Magazine articles praising this and that piece of power equipment are of dubious value at best. Those authors are usually slack-jawed mouth breathers just out of high school and get the facts pretty much wrong the majority of the time. Divide that rpm range by 3 and you are in the ball park of what it will see on the street. As Crazy Mopar Guy says they can be made to run pretty well on the street but I guarantee they aren't running as efficiently and with as much power as a dual plane manifold at street rpms. It isn't magic, just basic physics. A friend of mine ran a radical cross-ram w/ dual Holley 600s on his SBC. It ran but a dual plane would have been a lot better. As stated before, they were designed for WOT high speed drag racing and impressing chicks at Sonic on Friday night. Running them on a daily driver is a compromise as is all engine design.

02-08-2007 10:59 PM

topfuel

Quote:

Originally Posted by Crazy Mopar Guy

I've posted it so many times I'll just briefly add my two cents worth.

A proper PACKAGE will run with no troubles. I've ran tunnel ram 2x4bbls more than anybody I know, on daily driven work trucks, daily driven cars (the WIFE drove) and numerous high performance cars.
Not only were they responsive, trouble free, great cold and hot drivability, they also had power brakes on everything I built, some had mild cams, some not so mild, and all my stuff had to pass AirCare emissions testing.

Too many misconceptions about tunnel rams out there IMO.

You beat me to this post. I have been running tunnel rams on my street driven vehicles for over 20 years. As I have stated before, the main areas to focus on are 1) runner length-longer makes more torque, 2) plenum volume-use the smallest plenum you can find for increased throttle response, 3) proper carb sizing-use carbs with small venturies, 4) proper ignition advace curve-more important than you think and very often overlooked. Check out the pic below. It's a 406 sb with 9.6 comp and a Comp 280 Magnum cam. A completely incorrect Edelbrock Pro Ram II tunnel (rpm range 6500-10,000) with Holley 9776 465 cfm carbs. The engine idled at 850 and it never turned over 6000 rpm. With 3.08 gears, floor the pedal and smoke the tires from a dead stop. The car was a 71 Camaro. Trans was a turbo 400 with TCI 11" conv. This engine was my daily driver and the car was driven to many national shows. It can be done as has been proven to a few members of this board. PM me with a phone number and I'll be happy to talk to anyone about it.

Barry

02-08-2007 09:44 PM

Crazy Mopar Guy

I've posted it so many times I'll just briefly add my two cents worth.

A proper PACKAGE will run with no troubles. I've ran tunnel ram 2x4bbls more than anybody I know, on daily driven work trucks, daily driven cars (the WIFE drove) and numerous high performance cars.
Not only were they responsive, trouble free, great cold and hot drivability, they also had power brakes on everything I built, some had mild cams, some not so mild, and all my stuff had to pass AirCare emissions testing.

Too many misconceptions about tunnel rams out there IMO.

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